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July 4, 2000

7 Min Read
Rapid technologies poised for growth

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ARRK purchased SLA equipment from Plynetics Express, a failed service bureau, to boost its total of SLA machines to 40, making it the largest owner worldwide.

It would be easy to point to the Internet as the culprit of our collective addiction to speed, one that includes an increasing reliance on rapid prototyping and tooling. However, RP and RT answered the time-to-market needs of designers and molders even before the world got hooked on the Web. At the Rapid Prototyping & Manufacturing 2000 show (RP&M) held in May, a clear connection did emerge: It appears that rapid processes will accelerate due, in part, to support from cyberspace. In fact, Terry Wohlers, industry consultant, made this prediction: "In the not-too-distant future, I expect that most RP service providers and their customers will use the Internet to conduct a large part of their businesses."

Along with news about the Web, the RP industry seems to have rebounded from last year’s difficulties, including the demise of service bureaus Plynetics Express, Compression, and Formation. According to Wohlers’ 2000 State of the Industry Report, annual production of RP models and prototypes increased by 26 percent, and unit sales climbed 22 percent. Both figures refer to business activity for 1999. 

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POM commercialized the DMD process, which combines lasers, powdered metal, CAD, CAM, and CNC technologies to build tools layer by layer. Right: DMD mold cavities are built to near-net shape, and then finished to net dimensions using EDM.

Rapid Goes Online
Two new Web-based services introduced at RP&M 2000 heralded the beginning of RP and RT online. Spatial’s PlanetCAD division and Protomarket.com debuted their respective electronic marketplaces. Both are aimed at streamlining quotes, bids, communication, and data flow between RP service providers and their customers. The overall goal, according to both companies, is a reduction in the time it takes to receive a prototype part. 

Spatial's Bits2Parts.com is supported by anchor service bureau members Accelerated Technologies, ARRK, General Pattern, Eagle Design & Technology, Express Pattern, Prototech Engineering, and Soligen Technologies. To use the site, customers submit a Request For Quotation (RFQ) in a private work area and upload 3-D CAD models to a secure or possibly dedicated server. 

A comprehensive RFQ form, according to Spatial, is designed to remove ambiguities and deliver complete job specifications. Customers can choose one or several service bureaus to which the RFQ will be sent. A directory of service bureaus will also be available if members want to search for the best possible match based on region, capabilities, materials, and a variety of other criteria. 

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For casting applications, DSM Somos 9100 parts are easily removed from an RTV silicone mold.

Protomarket.com, a new site that went live in mid-May, also lets buyers post RFQs for new projects and provides a cost estimation tool that gives a rough idea of what the parts will cost. The site then identifies service bureaus with the appropriate capabilities to handle the job. Pulled from a database of prequalified providers, the selected service bureaus are then sent a request to submit quotes and comments. A virtual conference area can be used to discuss specific details privately with a potential vendor. Design data is protected because the buyer’s identity and CAD files can be released only to the vendor chosen by the buyer. 

In addition, a vendor rating system based on feedback from customers using the service lets buyers compare quality levels. Preferred and barred vendor lists allow buyers to control who can view and quote on the job. Another unique feature, a live help desk, lets site visitors conduct an online chat with customer service representatives during extended business hours. 

Real-time account summaries and RFQ tracking features help buyers manage RP projects. Customers participate in Protomarket.com free of charge, according to sales director Adrian Enochian, while service bureaus are charged a nominal transaction fee only when they win a job. 

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Automotive molder Roush created these map pockets in 12 hours using DSM Somos 9100 stereolithography resins, with properties comparable to polypropylene. Roush designer Archie Swanner compares the turnaround time to traditional methods that he says would have taken 12 days.

RT Advances
Ready for some new initials? POM (Precision Optical Mfg.) recently came on the scene with a rapid tooling technology called DMD (direct metal deposition). While the technology was patented at the University of Michigan’s Center for Laser-aided Manufacturing, POM commercialized it and added closed loop feedback, according to Tim Skszek, vp of operations. 

DMD is POM’s trade name for a process that creates metal parts and molds by focusing an industrial laser beam onto a tool steel workpiece or preform to create a molten pool of metal. To build layers on the workpiece, a small stream of powdered metal is injected into the melt pool. The laser beam then moves via an overhead gantry in a pattern defined by a CAD file using CNC control to create final geometry. 

Several features of DMD make it well-suited for generating production molds in tool steel. Most importantly, the process creates a fully dense mold or mold cavity in tool steel with no sintering or debinding. In addition, geometric accuracy and repeatability are a function of the overhead gantry (accurate to ±.0002 inch), and parts or tools are accurate to ±.005 inch. But because DMD is a near-net-shape process, tools are finished via EDM to achieve exact dimensions and surfaces. DMD also solves the problem of size limitations. While the process can deposit metal 24 inches at a time in the x, y, and z directions, larger tools can be indexed to complete the build. 

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Motorola created prototype parts for several of its products with SLA models from 3D Systems.

Customized cooling is another area in which DMD shines. To create conformal cooling channels, a sacrificial metal can be deposited in a specified pattern for each powder metal layer, in a "page-by-page" format. When the tool is complete, the sacrificial metal is burned out to create the channel. Also, by adding copper powder to specific areas, DMD can create heat sinks for directional cooling (part surfaces are cooled from a defined direction) to eliminate sinks on Class A surfaces. 

Time frames required to build a typical 10-by-10-inch tool range from two to five weeks. "The time it takes is related to physical size," says Skszek, "so a fascia tool is still a 20-week build." Costs are based on the magnitude of engineering effort and volume of deposition. For example, to reconfigure an existing tool using DMD, prices range from 20 to 30 percent of the original tool cost, with lead times of four weeks vs. 14 weeks to build a new tool. New DMD tools cost about 20 percent more than traditional tooling. 

Notes Skszek, "Although the original tool cost is higher, cycle times are reduced by 35 to 55 percent, and lead times average 12 to 16 weeks. Rather than building both prototype and production tooling, which averages 22 to 26 weeks, we can build one production tool, run prototypes, and modify it to reflect design changes." 

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A new material from 3D Systems and Ciba Specialty Chemicals, Cibatool SL 7540, mimics the properties of olefins and styrenics for more durable and flexible prototype parts.

The company acts as a service bureau, creating direct metal prototypes and tools as well as reworking existing tools. The company also manufactures the DMD equipment as an OEM; pricing for the system ranges from $700,000 to $900,000. 

Other useful Internet links:
DSM Somos www.dsmsomos.com
3D Systems www.3dsystems.com
Ciba Specialty Chemicals www.cibasc.com

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